Question

The total number of electrons present in $1.4 \,g$ of dinitrogen gas is

• A. $4.2 \times 10^{-23}$ electrons
• B. $3.2 \times 10^{23}$ electrons
• C. $4.2 \times 10^{23}$ electrons
• D. $3.2 \times 10^{-23}$ electrons

Answer 1

Answer: (C)

Number of moles of dinitrogen $= \frac{1.4}{28} = 0.05$
Number of molecules in $1.4 g$ of dinitrogen
$= 0.05 \times 6.022 \times 10^{23}$ molecules
$ = 0.3011 \times 10^{23}$ molecules $= 3.011 \times 10^{22}$ molecules
$\because 1$ molecule of dinitrogen has $14$ electrons.
$\therefore 3.011 \times 10^{22}$ molecules of dinitrogen have
$= 14 \times 3.011 \times 10^{22}$ electrons
$= 42.154 \times 10^{22}$ electrons $= 4.2154 \times 10^{23}$ electrons